Thermoluminescence Properties Research Articles

Influence of Al2o3 on Thermoluminescent, Bio Active and Elastic Properties of Nd3+ Ionic Calcio Phosphate Glasses

Calcio phosphate glass of Nd 3+ ions is well known for various photo (or) thermoluminescent applications. However, there is a lot of demand in biomedical technology, about high efficient photonic, thermoluminescent and bio compatible materials. In such a way, the Al x Ca y-x Nd 01 P 70 materials were synthesized and characterized by thermo, bio and photonic techniques. Structural studies suggests that the materials prepared were glassy. TL studies under different γ - irradiation dose range of Al x Ca y-x Nd 01 P 70 glasses are reported. The sample code ‘ A 5 ’ exhibiting good low AE (E ~ 0.997, E ~ 0.503 & E ~ 0.846 eV) and shape symmetry factor (~ 0.489) advised to be useful TL asset. Additionally, we have reported the results of Al 3+ ionic influence on vitro bio-activity studies of present glasses. Degradation results along with vitro bio-activity studies as a function Al 2 O 3 concentration advice sample code - A 5 is the useful biomedical resource.

Use of commercial pharmaceutical drug (Daktarin®) for retrospective/accidental/forensic thermoluminescence dosimetry

Retrospective/accidental dosimetry seeks for materials that can be used as probes for the dose assessment by means of several methods when there is no dose data available (e.g. from personal dosimeters). In the same respect, researchers also seek materials appropriate for forensic purposes, which would allow to identify the prior presence of radioactive materials at buildings, sites or even vehicles.To this direction, several solid-state drugs, which are ubiquitous, have also been studied as probes for the dose estimation in emergency situations. However, due to their heat-sensitive character, measurements were possible only with OSL. The scope of the present work is to identify a heat-resistant drug (Daktarin) and conduct, for the first time, a detailed study of the thermoluminescence properties of it along with computerized curve deconvolution analysis which would shed light on the traps involved.Results indicate that the glow curve of Daktarin has at least three peaks that can be used for dosimetric purposes, since they exhibit linear dose response for doses up to 20 Gy, do not exhibit any sensitization, have high lifetime and their stability with time is good, since an appreciable signal remains unaffected even 3 months post irradiation. All the above were validated conducting dose recovery tests and successfully calculating the unknown delivered dose for various periods after the irradiation of the samples. The new findings are very supportive and point towards the efficient use of commercial pharmaceuticals as probes for retrospective/accidental/forensic dosimetry using thermoluminescence.

Synthesis and thermoluminescence properties of MgAl2O4:Ca laser-sintered ceramics

Abstract Ceramic materials are low cost and have a good thermal and mechanic resistance which are suitable characteristics for a good dosimeter. A new Ca-doped MgAl2O4 ceramic material was produced by the first time by the laser sintering method. Thermoluminescence (TL) properties as a function of the exposure to ionizing radiation were investigated. X-ray diffraction of the sintered samples showed single crystalline phase corresponding to the cubic spinel structure. SEM images reveal the microstructure with homogenous and faceted grains and low porosity. TL readouts were performed with a linear heating rate were performed after irradiation with beta particles (doses ranging from 0.02 to 5 Gy). The TL glow-curve shows a single and wide peak centered at about 170 °C with a linear dose response, good repeatability (~ 1%) and immediate fading that stabilizes after ~ 16 h with 80% of the initial intensity. The lowest detectable dose (LDD) was also evaluated at ~ 20 μGy. By applying the Tm-Tstop method to analyze the glow curve, it was found a behavior characteristic of closely overlapping or a quasi-continuum of peaks. Initial rise, peak shape of the TL glow curve, the TL glow curve area, and glow curve fitting methods were used to obtain the kinetic parameters of the glow peak. In general, the TL results suggest that this material might be used in dosimetric applications considering the studied dose range.

The effect of copper on the structural and thermoluminescence properties of aluminium borate

The thermoluminescence of aluminium borate doped to different concentrations of copper is reported. Samples of Al2(B4O7)3:Cu were prepared by high-temperature solid-state sintering. Scanning electron microscopy showed a difference in the grain size for the copper doped and undoped aluminium borate with particulates of the undoped sample in the size 60–80 nm whereas those of the undoped sample were in the range 40–50 nm. Studies using Fourier transform infrared spectroscopy showed that copper doping of aluminium borate reduces transmittance and results in more absorbance in the various spectral regions. Thermoluminescence from all samples measured at 1oCs−1 following irradiation to 150 Gy shows a prominent peak near 98 °C with a secondary, weaker-intensity peak at 168 °C.Both peaks are subject to non-first-order kinetics and the dose response is affected by doping.

The effect of dose on thermoluminescence of ScPO4:Eu3+ ceramic

Depending on the dose of ionizing radiation, ScPO4:0.1%Eu3+ sintered ceramic presents significantly different thermoluminescent properties. Despite a thermoluminescent peak around 90 °C which appears upon small doses (up to tens of mGy) it also shows strong thermoluminescence at 240 °C but only after exposure to higher doses. In both cases, the thermoluminescence is generated by Eu3+ ions, which also serve as electron traps. Recognition of the relevant hole traps responsible for the thermoluminescent peaks needs more comprehensive research using such tools as advanced EPR spectroscopy at different temperatures. At room temperature, the thermoluminescence peak at 240 °C is very resistant to fading hardly showing any loss of intensity within 24 h. The peak at 90 °C fades continuously at ambient conditions and after 24 h its intensity drops to about 10% of its original strength. Hence, this component is responsible for the hours-lasting persistent luminescence of the ScPO4:0.1%Eu3+ ceramic.

Synthesis and luminescence properties of RE3+ (re = eu3+, Dy3+) activated CaSr2(PO4)2 phosphors for lighting and dosimetric applications

A series of RE3+ (RE = Eu3+, Dy3+) activated CaSr2(PO4)2 phosphors were successfully synthesized by the Solid-State Diffusion method at high temperature. X-ray diffraction (XRD) pattern and Fourier transform infrared (FT-IR) spectra explained the structural properties and crystalline nature of the prepared sample. The Scanning Electron Microscopy (SEM) study represents particle size and morphological behavior of the prepared sample. The luminescence properties of the prepared phosphor were investigated by Photoluminescence (PL) and Thermoluminescence (TL) techniques. The PL properties of Eu3+ activated CaSr2(PO4)2 phosphors monitored under near-ultraviolet excitation at 395 nm, exhibited two strong, orange and red emission peaks at 593 nm and 615 nm respectively corresponding to the characteristic 5D0→7F1 and 5D0→7F2 transitions of Eu3+ ions. Further, Dy3+ activated CaSr2(PO4)2 phosphors monitored under 350 nm excitation wavelength, exhibited two strong, blue, and yellow emission peaks at 481 nm and 572 nm respectively, corresponding to the characteristic 4F9/2→6H15/2 and 4F9/2 → 6H13/2 transitions of Dy3+ ion. The CIE chromaticity diagram shows high color purity and excellent chromaticity coordinates and it also shows the presence of emission bands in the visible spectrum. The TL properties of (RE = Eu3+, Dy3+) activated CaSr2(PO4)2 phosphors were investigated after irradiating the samples with 75 MeV Oxygen ion beam and Gamma rays. CaSr2(PO4)2:Eu samples show TL response linearity in the fluence range 5 × 1010 ions/cm2 to 1 × 1011 ions/cm2 whereas CaSr2(PO4)2:Dy samples show linearity in the range 5 × 1010 ions/cm2 to 5 × 1011 ions/cm2 when irradiated with 75 MeV O6+ ion beam. Further γ-ray irradiated CaSr2(PO4)2 samples show TL response linearity for dose range 1.75 kGy to 21.06 kGy when activated by Eu and 0.116 kGy to 2.32 kGy when activated by Dy. So, CaSr2(PO4)2 activated by RE3+ (RE = Eu3+, Dy3+) phosphor is a promising candidate for lighting and dosimetric applications.

Luminescence of Bi3+ and Bi2+ ions in novel Bi-doped SrAl4O7 phosphor

Bismuth-doped SrAl4O7 powders were synthesized via modified Pechini process and their photoluminescence, radioluminescence and thermoluminescence properties were studied and discussed. Obtained results showed that in studied materials bismuth is present in two valence states, Bi3+ and Bi2+. Upon UV excitation SrAl4O7:Bi powders yield broad multicomponent luminescence in the 350–670 nm range, associated with the 3P0,1 → 1S0 transition of Bi3+ ions, and the most intense component located in green (λmax = 515 nm) part of spectrum. It was found that the emission spectral distribution is excitation wavelength-dependent. By changing the excitation wavelength in the 270–340 nm range the emission colour can be modulated from blue, through bluish-cyan to green. The studied phosphors also showed broad-band 2P3/2 → 2P1/2 Bi2+ emission in deep red region centered at around 710 nm. This luminescence was found predominant in radioluminescence and thermoluminescence spectra, which is deemed unique for bismuth-doped materials. The Bi2+ 630–830 nm emission might be attractive for bioimaging as it appears in the Ist biological window and may be utilized for deep red scintillation.

Significant enhancement of blue photoluminescence intensity of Dy3+ modified Sr6Ca4(PO4)6F2:Eu2+ phosphors

Blue-emitting phosphors Sr6Ca4(PO4)6F2:Eu2+ (SCPF:Eu2+), Sr6Ca4(PO4)6F2:Eu2+,Dy3+ (SCPF:Eu2+,Dy3+) and Sr6Ca4(PO4)6F2:Eu2+,Dy3+,Si4+ (SCPF:Eu2+,Dy3+,Si4+) with apatite structure were successfully synthesized by traditional solid-state reaction under reducing atmosphere. Eu2+, Dy3+ and Si4+ ions occupy the corresponding sites of Sr2+, Ca2+ and P5+. Strong broad blue photoluminescence band is exhibited in SCPF:Eu2+,Dy3+ phosphor ranging from 400 to 550 nm centered at 455 nm and Dy3+ ions are vital in creating traps. Emission intensity of Eu2+, Dy3+ co-doped SCPF:0.02Eu2+,0.02Dy3+ is about 1.8 times that of SCPF:0.02Eu2+ and electron trap centers serve as energy transporting media. To further elucidate the formation and effect of the specific defect on the luminescence of SCPF:0.02Eu2+,0.02Dy3+ phosphor, the thermoluminescence properties, decay curves and thermal stability studies were performed while the Si4+-P5+ charge compensated phosphor SCPF:0.02Eu2+,0.02Dy3+,0.02Si4+ was prepared as a contrast. All the results of present work indicate that Dy3+ co-doping can obviously enhance photoluminescence intensity of SCPF:0.02Eu2+ by the electron traps generated by non-equivalence replacement of Dy3+-Ca2+.

Natural dead sea salt and retrospective dosimetry.

Accidents resulting in widespread dispersal of radioactive materials have given rise to a need for materials that are convenient in allowing individual dose assessment. The present study examines natural Dead Sea salt adopted as a model thermoluminescence dosimetry system. Samples were prepared in two different forms, loose-raw and loose-ground, subsequently exposed to 60Co gamma-rays, delivering doses in the range 2-10Gy. Key thermoluminescence (TL) properties were examined, including glow curves, dose response, sensitivity, reproducibility and fading. Glow curves shapes were found to be independent of given dose, prominent TL peaks for the raw and ground samples appearing in the temperature ranges 361-385 ºC and 366-401 ºC, respectively. The deconvolution of glow curves has been undertaken using GlowFit, resulting in ten overlapping first-order kinetic glow peaks. For both sample forms, the integrated TL yield displays linearity of response with dose, the loose-raw salt showing some 2.5 × the sensitivity of the ground salt. The samples showed similar degrees of fading, with respective residual signals 28days post-irradiation of 66% and 62% for the ground and raw forms respectively; conversely, confronted by light-induced fading the respective signal losses were 62% and 80%. The effective atomic number of the Dead Sea salt of 16.3 is comparable to that of TLD-200 (Zeff 16.3), suitable as an environmental radiation monitor in accident situations but requiring careful calibration in the reconstruction of soft tissue dose (soft tissue Zeff 7.2). Sample luminescence studies were carried out via Raman and Photoluminescence spectroscopy as well as X-ray diffraction, ionizing radiation dependent variation in lattice structure being found to influence TL response.

Role of Bi2O3 in altering the structural, optical, mechanical, radiation shielding and thermoluminescence properties of heavy metal oxide borosilicate glasses

With the main intention of developing a transparent radiation shielding as well as a gamma dosimetric material, a series a heavy metal oxide borosilicate glass of composition (60-x) B2O3- 20SiO2- xBi2O3- 10ZnO- 10BaO with x = 0, 5, 10, 15 mol% was prepared by melt- quench technique. The glasses obtained were all transparent, except Bi-15 sample which is opaque and black in colour. The darkening is due to thermal reduction of Bi3+ ions, which is clearly indicated by absorption band around 377nm. XRD patterns showed the absence of crystalline peaks even in the opaque Bi-15 sample, confirming the glassy nature of all glasses. Furthermore, the structural changes in the glasses were confirmed with density measurement and FTIR studies. The Vickers hardness test done on transparent samples proved their higher mechanical strength, along with the theoretical calculation of elastic constants. The detailed analysis of gamma and neutron radiation shielding parameters for all the glasses was done using Photon Shielding and Dosimetry (PSD) software. The results suggested that the ϒ-ray shielding capacity increased, whereas the neutron attenuation ability decreased with the successive addition of Bi2O3. The opacity of Bi-15 can create problem in certain applications where transparency is needed. In order to assess the possibility of transparent glasses to be used as gamma dosimeter, they were irradiated with gamma rays of 1.25 MeV and thermoluminescence (TL) glow curves were recorded. An interesting behaviour of quenching of TL intensity for initial addition and enhancement of TL intensity for further addition of Bi2O3 was observed. The linearity of the dose- response curve for Bi-10 sample in two regions of gamma doses 100 Gy-3 kGy and 5- 50 kGy, showcased the chances of Bi-10 sample to be used as TL dosimeter for both low and high doses.

Structural, optical and thermoluminescence properties of newly developed MnKB: Er3+ glass system

Erbium-doped manganese potassium borate glasses have been synthesized to study their physical, structural, optical and thermoluminescence properties. These glasses were prepared by melt quenching technique and characterized by using various techniques X-ray diffraction (XRD), Fourier transform infrared (FTIR), UV-visible (UV) and thermoluminescence (TL). Through FTIR spectroscopy the presence of various structural units has been studied. From Kubelka- Munk method, the optical band gap energy (Eopt) corresponding to the allowed direct and indirect transitions and the Urbach energy (E) values of the prepared glasses were determined. The impact of different concentration of Er2O3 on the TL intensity of the glass samples has been analyzed. The recorded glow curves show a single prominent peak around 398–422 K and the trapping parameters exhibit the kinetics of second order. With a good linear correlation coefficient, the glass sample E5 is a suitable candidate for medical and personal radiation measurements purposes.

Effect of Yb3+ codopant on the upconversion and thermoluminescent emission of Sr2CeO4:Er3+, Yb3+ phosphors

This work presents the structural, morphological, upconversion luminescence and Thermoluminescence properties of Sr2CeO4:Er3+,Yb3+ (SCO:Er, Yb) phosphors synthesized by a simple combustion method. The X-ray diffraction technique revealed that all the samples maintained their orthorhombic phase even for Yb concentrations as high as 12 mol%. Moreover, the morphological analysis by scanning electron microscopy (SEM) pointed out that SCO microparticles with sizes in the range of 0.2 μm–7.2 μm were obtained in samples doped with 0–3 mol% of Yb, but coalesced microparticles were observed for Yb concentrations from 7 to 12 mol%. The luminescence measurements demonstrated that the SCO: Er, Yb microparticles produced red and green upconversion emission bands and the red component increases with the Yb concentration. Also, the TL signals were recorded after solar/UV irradiation and found TL emission bands in the range of 60–150 °C and 150–350 °C. The traps responsible of the TL emissions were the oxygen vacancies.

Improved Thermoluminescence Properties of Natural NaCl Salt Extracted From Mediterranean Sea Water Relevant to Radiation Dosimetry

Thermoluminescence (TL) technique has been used to characterize and determine the dosimetric properties of natural sodium chloride (NaCl) salt extracted from the Seawater of the Mediterranean Sea. The TLD grade material was prepared by evaporation and annealing the powder obtained from the aqueous solution. The TL properties include the response to theb-irradiation dose and the effects resulting from annealing up to 700oC, heating rate and fading. The analysis involve using total Glow Curve Deconvolution (GCD) to separate the inherent overlapping TL-peaks and determine the TL characteristics and the trapping parameters using general order (GO)kinetics (activation energy, kinetic order, peak position of trap and the frequency factor). The GL-curves exhibit well defined TL-peaks around 140oC, 225oC and 380oC and response depending on the annealing temperature due to variations due to formation of the structural defects. A linear response was noticed over the delivered range of absorbed doses up to 4Gy. The fading results gave evidence that TL emission is due to a redistribution of trapping levels and indicate that the prominent TL-peak near 225oCis useful for TL-dosimetric applications.

Particles size increase assisted enhancement of thermoluminescence emission in gadolinium and dysprosium oxide doped phosphate glasses

This paper presents results of research on the influence of particles size of Gd2O3 and Dy2O3 doped phosphate glasses on the intensity of thermoluminescence (TL) signals. The obtained glasses were investigated towards potential application in high dose radiation measurements. Simultaneously, next to the glass powders, the glass/polytetrafluoroethylene composite detectors were prepared and used to study dosimetric signal dependencies and influence of glass particles size on their TL behavior. The thermoluminescence dosimetry (TLD) technique was used as the main investigation tool to study detectors dose response. Next to the sole effect of the glass particles size, the results present also an influence of the rare earth dopants on intensity of TL signal. The obtained data present the dosimetric properties of raw and doped phosphate glass (effect of particles size, dose response and radiation sensitivity). It has been found that incorporation of rare earth oxides into glass matrix changes substantially the thermoluminescent behavior of a pure phosphate glass. The highest luminescence yield was found for the samples with the largest glass particles (up to 1000 μm). The incorporation of dysprosium or gadolinium ions into the glass matrix influences both the structure of the electron traps in the glass matrix and TL emission intensity vs. particles size. The dependence of the thermoluminescence signals intensity vs. particles size for all samples can be considered as a saturation type curve. The investigated phosphate glasses exhibit good thermoluminescence properties for the high energy beta radiation dose measurement applications.

Development of a mechanically resistant fluorite-based pellet to be used in personal dosimetry

The Laboratory of Dosimetry of the University of Sao Paulo performs the external individual monitoring of workers exposed to X and gamma rays applying thermoluminescence (TL) technique. Two types of detectors are used in this service: TLD-100 (LiF:Mg,Ti) and pellets made with natural green fluorite cold pressed with sodium chloride as agglutinant (CaF2:NaCl). Due to the mechanical fragility of the CaF2:NaCl pellet, a new detector has been developed using a commercial adhesive as a binding agent aiming to increase the mechanical resistance. TL properties of the new designed pellet were investigated aiming the use in personal dosimetry and the substitution of the currently in use detectors. Optically stimulated luminescence (OSL) measurements were also performed in order to find its potential use as an OSL dosimeter.

Structural, compositional and thermoluminescence properties of microcline (KAlSi3O8)

Structural, compositional and thermoluminescence (TL) properties of microcline (KAlSi3O8) collected from Northeastern region of India are reported. The structural and compositional analyses confirm the presence of microcline phase in the sample. The average crystallite size of microcline is estimated as (89.05 ± 0.13) nm. TL measured at 1 °C/s from a sample irradiated to 40 Gy produces five glow peaks at 90, 123, 166, 298 and 391 °C. Of these, the peak at 123 °C is the most intense. An analysis of the dependence of peak maxima (Tm) with preheat temperature (Tstop) reveals that the glow curve is composed of several closely spaced overlapping peaks. The dependence of the activation energy (E) on preheat temperature is consistent with a continuum distribution of electron traps with activation energy between 0.71 eV and 1.15 eV. The dose response of the prominent peak at 123 °C is quantitatively superlinear within the range 1–100 Gy of beta irradiation dose. The TL fades between irradiation and measurement in a manner suggestive of quantum tunnelling of trapped electrons between the trapping levels of microcline.

Impact of Na2-EDTA and urea on structure and optical properties of pure neodymium oxide

Nano pebbles of pure neodymium oxide is synthesized by the solution combustion method and they exhibit room temperature photoluminescence and thermoluminescence properties. Powder X-ray diffraction pattern reveals A-type hexagonal structure. Surface morphology is visualized by the field emission scanning electron microscopy. The visualized images are regular and irregular shapes with smooth surface. Energy dispersive X-ray spectroscopy reveals the existence of Nd, O and Na elements. X-ray photoelectron spectroscopy reveals the signature of all elements exist in the sample. The diffused reflectance spectrum is used to evaluate the optical band gap energy. Fourier transformed-infrared spectrum confirms the existence of Nd and O bond. Raman spectrum peaks are assigned and confirms A-type hexagonal phase. PL emission is observed in UV, blue, green and red region and the peaks are located at 325, 347, 380, 385, 422, 445, 485, 530, 605, 625, 650, 690 and 750 nm. The activation energies and the frequency factors of thermoluminescence are calculated. The synthesized Nd2O3 is a promising material for white light emitting diodes and the supra linearity features of TL is to be a potential candidate for dosimeters applications.

Surface adaptation prompted enhanced photo and thermoluminescence properties of Dy3+ doped wollastonite nanophosphor

The novel CaSiO3:Dy3+ (1–11 mol %) nanophosphors synthesized via simple solution combustion route and covered with silica (SiO2) by the Stöber method are reported in the present work. The X ray diffraction analysis verifies the phase purity of the synthesized samples. The diffraction peaks observed in the recorded powder x-ray diffraction patterns are in good relation with those known for the CaSiO3 structure. The photoluminescence and thermoluminescence properties of SiO2@CaSiO3:Dy3+ (3 mol %) nanophosphors were extensively investigated. The 3-fold enhancement in the photoluminescence intensity of nanophosphors after surface coating was observed, that may be due to light diffraction and multiplied by shell SiO2. The utility of the prepared samples in white light emitting diodes was confirmed by studying photometric properties. The thermoluminescence study of the samples with different γ-ray doses showed good linearity up to 4 kGy and, thereafter, the sub-linear behavior was noticed. The variation in the thermoluminescence intensity arises as a consequence of competition between different trapping centers. The aforementioned results signify that the present material was highly useful for display and dosimetry applications.

Comparison of the thermoluminescence properties of NaCaPO4:Dy3+ phosphors irradiated by 75 MeV C6+ ion and γ-rays

The thermoluminescence (TL) properties of sol-gel synthesized NaCaPO4:Dy3+ phosphors irradiated by different sources of γ and carbon-ion beam form the main focus of this article. The TL study of NaCaPO4:Dy3+ phosphor was discussed for the samples irradiated by different doses of Co60 γ-rays, Cs137 γ-rays and a 75 MeV C6+ ion-beam. The effects of irradiation on the structural and photoluminescence (PL) properties were explored on the basis of results obtained from X-ray diffraction (XRD), Fourier-transform infrared spectroscopy and PL emission spectra. Not much change was observed in the XRD patterns, except for the loss of crystallinity due to the radiation exposure. Different TL characteristics such as linearity, dose-response and TL signal fading were also studied and the trapping parameters were determined using the Glow Curve Deconvolution method. NaCaPO4:xDy3+ has shown potential to be used for TL dose measurements of γ-radiation and also for C6+-ion beam measurements.

Thermoluminescence properties of Strontium borophosphate doped with Praseodymium and enhancement with uranyl codoping

Strontium borophosphate (SrBPO5) phosphors undoped and doped with Pr3+ and/or UO22+ were prepared by conventional high-temperature solid-state reaction method. The X-ray diffraction (XRD) and Raman spectroscopy studies confirmed the phase purity of the prepared samples. All the samples were irradiated with gamma radiation to study their thermoluminescence (TL) properties. The undoped SrBPO5 showed a very weak single glow peak at 415 K. whereas SrBPO5 doped with Pr3+/UO22+ exhibited multiple prominent glow peaks in the range of 395–460 K. Three glow peaks were also observed in case of SrBPO5 codoped with Pr3+ and UO22+. Interestingly, one of the three glow peaks were found to be in the range of 480–620 K and was very sensitive to the gamma radiation compared to the singly doped phosphor. The trap parameters were calculated for the glow peaks to understand the mechanism and order of kinetics. The dose-response of the dosimetric glow peak was studied in the range of 1 mGy to 1 kGy. TL emission spectrum showed characteristic emission of Pr3+ though no such emission was observed for UO22+. A probable TL mechanism has proposed for the TL emission coming from the SrBPO5 doped with Pr3+ and/or UO22+.